python 中如何调用FCM算法

以下代码调试通过：

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1234567class LuciaClass:  # 定义类    def luciaprint(self, text):  # 类里面的方法        print('\n', text)  # 方法就是输出 text  x = LuciaClass()  # 方法的实例 xx.luciaprint('today is a bad day ~~~')  # 实例调用类方法

运行效果：

在matlab中做模糊C均值聚类（fcm）算法如何体现初始隶属度？

我贴部分FCM的Matlab代码：

expo = options(1); % Exponent for U

max_iter = options(2); % Max. iteration

min_impro = options(3); % Min. improvement

display = options(4); % Display info or not

obj_fcn = zeros(max_iter, 1); % Array for objective function

U = initfcm(cluster_n, data_n); % Initial fuzzy partition

% Main loop

for i = 1:max_iter,

[U, center, obj_fcn(i)] = stepfcm(data, U, cluster_n, expo);

if display,

fprintf('Iteration count = %d, obj. fcn = %f\n', i, obj_fcn(i));

end

% check termination condition

if i 1,

if abs(obj_fcn(i) - obj_fcn(i-1)) min_impro, break; end,

end

end

其中

U = initfcm(cluster_n, data_n); % Initial fuzzy partition

这个就是初始化划分矩阵，随机产生一个隶属度矩阵，

代码如下：

U = rand(cluster_n, data_n);

col_sum = sum(U);

U = U./col_sum(ones(cluster_n, 1), :);

上面就是它初始化的一个隶属度矩阵，

cluster_n行，data_n列。

即一列中从上到下表示每个样本隶属与每一类的隶属度。

然后在算法中不断迭代，

最后得到的还是如此大的一个矩阵，代表每个样本隶属与每一类的隶属度

然后选择最大的那个就是，它就属于那一类。

matlab中的功能函数FCM如何使用

模糊C均值聚类算法，可将输入的数据集data聚为指定的cluster_n类

【函数描述】

语法格式

[center, U, obj_fcn] = FCM(data, cluster_n, options)

用法：

1. [center,U,obj_fcn] = FCM(Data,N_cluster,options);

2. [center,U,obj_fcn] = FCM(Data,N_cluster);

输入变量

data ---- n*m矩阵,表示n个样本,每个样本具有m维特征值

cluster_n ---- 标量,表示聚合中心数目,即类别数

options ---- 4*1列向量，其中

options(1): 隶属度矩阵U的指数，1(缺省值: 2.0)

options(2): 最大迭代次数(缺省值: 100)

options(3): 隶属度最小变化量,迭代终止条件(缺省值: 1e-5)

options(4): 每次迭代是否输出信息标志(缺省值: 0)

输出变量

center ---- 聚类中心

U ---- 隶属度矩阵

obj_fcn ---- 目标函数值

java一个整数除以一个小数为什么的到小数

Java中如果除运算符“/”，在不加任何限制的情况下，两个整数相除，得到的是整数，小数点后的被舍弃。但是有些场景下我们需要拿到除得的小数，还要指定位数的小数。这时候有以下处理方法：

1.使用DecimalFormat来限定得到的小数位数

int pcm = 98;

int fcm = 11;

DecimalFormat df = new DecimalFormat("0.00");

double tmpVal = Double.parseDouble(df.format((double) pcm/(pcm+fcm)));

//get value 0.89

注意，它默认返回的是String，如果需要double/float要做一下转换。

2.直接使用Decimal运算

@Test

public void testDecimalOper(){

int pcm = 94;

int fcm = 11;

BigDecimal pcmbd = new BigDecimal(pcm);

BigDecimal fcmbd = new BigDecimal(fcm);

BigDecimal rate = new BigDecimal(0.00);

rate = pcmbd.divide(pcmbd.add(fcmbd), 2, RoundingMode.HALF_UP);

System.out.println(rate);//0.90

}

float/double在工程运算中使用的比较多，在商业计算中使用Decimal类型的比较多。(注：

在《Effective Java》这本书中也提到这个原则，float和double只能用来做科学计算或者是工程计算，在商业计算中我们要用 java.math.BigDecimal，另外，我们如果需要精确计算，要用String来够造BigDecimal。在《Effective Java》一书中的例子是用String来够造BigDecimal的。(注意：divide方法中推荐使用枚举RoundingMode.HALF_UP)

)

两种方式都可以。推荐使用第二种方式来处理精度和round mode的设置。

附BigDecimal rouding mode:

/**

* Rounding mode to round away from zero. Always increments the

* digit prior to a nonzero discarded fraction. Note that this rounding

* mode never decreases the magnitude of the calculated value.

*/

public final static int ROUND_UP = 0;

/**

* Rounding mode to round towards zero. Never increments the digit

* prior to a discarded fraction (i.e., truncates). Note that this

* rounding mode never increases the magnitude of the calculated value.

*/

public final static int ROUND_DOWN = 1;

/**

* Rounding mode to round towards positive infinity. If the

* {@code BigDecimal} is positive, behaves as for

* {@code ROUND_UP}; if negative, behaves as for

* {@code ROUND_DOWN}. Note that this rounding mode never

* decreases the calculated value.

*/

public final static int ROUND_CEILING = 2;

/**

* Rounding mode to round towards negative infinity. If the

* {@code BigDecimal} is positive, behave as for

* {@code ROUND_DOWN}; if negative, behave as for

* {@code ROUND_UP}. Note that this rounding mode never

* increases the calculated value.

*/

public final static int ROUND_FLOOR = 3;

/**

* Rounding mode to round towards {@literal "nearest neighbor"}

* unless both neighbors are equidistant, in which case round up.

* Behaves as for {@code ROUND_UP} if the discarded fraction is

* ≥ 0.5; otherwise, behaves as for {@code ROUND_DOWN}. Note

* that this is the rounding mode that most of us were taught in

* grade school.

*/

public final static int ROUND_HALF_UP = 4;

/**

* Rounding mode to round towards {@literal "nearest neighbor"}

* unless both neighbors are equidistant, in which case round

* down. Behaves as for {@code ROUND_UP} if the discarded

* fraction is {@literal } 0.5; otherwise, behaves as for

* {@code ROUND_DOWN}.

*/

public final static int ROUND_HALF_DOWN = 5;

/**

* Rounding mode to round towards the {@literal "nearest neighbor"}

* unless both neighbors are equidistant, in which case, round

* towards the even neighbor. Behaves as for

* {@code ROUND_HALF_UP} if the digit to the left of the

* discarded fraction is odd; behaves as for

* {@code ROUND_HALF_DOWN} if it's even. Note that this is the

* rounding mode that minimizes cumulative error when applied

* repeatedly over a sequence of calculations.

*/

public final static int ROUND_HALF_EVEN = 6;

/**

* Rounding mode to assert that the requested operation has an exact

* result, hence no rounding is necessary. If this rounding mode is

* specified on an operation that yields an inexact result, an

* {@code ArithmeticException} is thrown.

*/

public final static int ROUND_UNNECESSARY = 7;

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